Summary :
The authors describe the case of a 32 years old man with Crohn's disease who has developped sinonasal and tracheal localizations. The review of the literature, quite poor, allows to find some cases of nasal involvement in Crohn's disease and few associations between this illness and others systemic diseases as Wegener's disease or relapsing polychondritis. Among these diseases, we can find atypical conditions mixing different features of the most classical systemic diseases, which are called "overlap syndromes". The case we report illustrate these questions relative to the diagnosis. To conclude, it may be important to point at the difficulties of the anatomopathological diagnosis and the interest of the iterative biopsies. Regular follow-up can help us to identify systemic disease with the research of new extra-sinonasal symptoms.